Mistakes Made in U4

What is the time taken for a capacitor to reach maximum voltage

Time constant multiplied by 5

Why are high energies of colliding particles required to produce particles with larger masses (3)

- Mass is conserved due to E=Mc^2

- Energy of colliding particles must be higher as the produced particle must have a larger mass

- Additional energy comes from KE of colliding particles

Why would be the difference in time taken for a magnet to fall through a metal tube with a slit compared to without a slit

- As the magnet falls through each tube, magnetic field lines are cut. This creates a change in magnetic flux linkage

- This change in linkage creates an induced emf in both tubes

- Current flows through tubes, as they act like a closed circuit

- A magnetic field is created due to the current

- The tube with a slit has a smaller current due to a shorter path due to the slit

- Therefore the magnetic force that opposes the change creating the emf is smaller, so the magnet falls quicker through the tube with a slit

Why were alpha particles the best choice for Rutherford's experiment compared to beta or gamma [4]

- Gamma rays are not charged

- Therefore wouldn't experience electrostatic repulsion like alpha particles did

- Beta particles are highly penetrating

- Therefore wouldn't interact with the gold foil

How does banking allow a plane to fly in a circular path [4]

- Vertical component of the lift force is equal to the weight

- No vertical resultant force means no vertical acceleration

- Horizonal component of lift force is equal to the centripetal force

- So it follows a circular path

Lenz's Law

The induced emf is set up in a direction to produce effects that oppose the change causing it.

emf=-d(Nphi)/d(t)

Faraday's Law

The magnitude of the induced emf is directly proportional to the rate of change of magnetic flux linkage

Why do gaps between drift tubes increase in the first part of a LINAC but remain the same in the second part of the LINAC? [6]

- Electrons accelerate in the gaps

- Frequency of the AC supply is constant

- Time taken for electrons to travel between adjacent tubes is constant

- Electrons travel further in a fixed time when accelerating as v=s/t

- As the electron reaches the speed of light

- The electron doesn't experience further acceleration so speed becomes constant and therefore distance in a set time stays constant.

How do particle detectors show a particle is neutral [2]

- No track created

- Particles have opposite charge and charge is conserved in particle interactions

How do particles detect particles [2]

- Particles are ionising

- A track is formed by the ionising particles produced

Function of Capacitor

- The capacitor is an energy store

- The overall charge on a capacitor is 0

- The capacitor separates charge

Why are high energy particles used to study the structure of nucleons? [3]

- High energy so particles have high momentum

- High momentum so that De Broglie wavelength is small

- Studying nucleons requires wavelengths of the order of nucleon size